Rate

Any

Regularity

Regular

P waves

Upright and uniform

PRI

> 0.20

QRS

0.08-0.12

Rate

60-100

Regularity

Slightly irregular

P waves

Bizarre/unusual

PRI

< 0.20

QRS

0.08-0.12

Rate

Any

Regularity

Regularly Irregular

P waves

Upright and uniform

PRI

Cyclic pattern of conducted and dropped beats

QRS

0.08-0.12